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15#include "qemu/osdep.h"
16#include "qemu/cutils.h"
17#include "trace.h"
18#include "block/block_int.h"
19#include "block/blockjob_int.h"
20#include "qapi/error.h"
21#include "qapi/qmp/qerror.h"
22#include "qemu/ratelimit.h"
23#include "sysemu/block-backend.h"
24
25enum {
26
27
28
29
30
31 COMMIT_BUFFER_SIZE = 512 * 1024,
32};
33
34typedef struct CommitBlockJob {
35 BlockJob common;
36 BlockDriverState *commit_top_bs;
37 BlockBackend *top;
38 BlockBackend *base;
39 BlockDriverState *base_bs;
40 BlockdevOnError on_error;
41 bool base_read_only;
42 bool chain_frozen;
43 char *backing_file_str;
44} CommitBlockJob;
45
46static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base,
47 int64_t offset, uint64_t bytes,
48 void *buf)
49{
50 int ret = 0;
51
52 assert(bytes < SIZE_MAX);
53
54 ret = blk_co_pread(bs, offset, bytes, buf, 0);
55 if (ret < 0) {
56 return ret;
57 }
58
59 ret = blk_co_pwrite(base, offset, bytes, buf, 0);
60 if (ret < 0) {
61 return ret;
62 }
63
64 return 0;
65}
66
67static int commit_prepare(Job *job)
68{
69 CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
70
71 bdrv_unfreeze_backing_chain(s->commit_top_bs, s->base_bs);
72 s->chain_frozen = false;
73
74
75
76 blk_unref(s->base);
77 s->base = NULL;
78
79
80
81 return bdrv_drop_intermediate(s->commit_top_bs, s->base_bs,
82 s->backing_file_str);
83}
84
85static void commit_abort(Job *job)
86{
87 CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
88 BlockDriverState *top_bs = blk_bs(s->top);
89
90 if (s->chain_frozen) {
91 bdrv_unfreeze_backing_chain(s->commit_top_bs, s->base_bs);
92 }
93
94
95 bdrv_ref(top_bs);
96 bdrv_ref(s->commit_top_bs);
97
98 if (s->base) {
99 blk_unref(s->base);
100 }
101
102
103
104 block_job_remove_all_bdrv(&s->common);
105
106
107
108
109
110
111
112
113 bdrv_replace_node(s->commit_top_bs, backing_bs(s->commit_top_bs),
114 &error_abort);
115
116 bdrv_unref(s->commit_top_bs);
117 bdrv_unref(top_bs);
118}
119
120static void commit_clean(Job *job)
121{
122 CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
123
124
125
126
127 if (s->base_read_only) {
128 bdrv_reopen_set_read_only(s->base_bs, true, NULL);
129 }
130
131 g_free(s->backing_file_str);
132 blk_unref(s->top);
133}
134
135static int coroutine_fn commit_run(Job *job, Error **errp)
136{
137 CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
138 int64_t offset;
139 uint64_t delay_ns = 0;
140 int ret = 0;
141 int64_t n = 0;
142 void *buf = NULL;
143 int bytes_written = 0;
144 int64_t len, base_len;
145
146 ret = len = blk_getlength(s->top);
147 if (len < 0) {
148 goto out;
149 }
150 job_progress_set_remaining(&s->common.job, len);
151
152 ret = base_len = blk_getlength(s->base);
153 if (base_len < 0) {
154 goto out;
155 }
156
157 if (base_len < len) {
158 ret = blk_truncate(s->base, len, false, PREALLOC_MODE_OFF, NULL);
159 if (ret) {
160 goto out;
161 }
162 }
163
164 buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE);
165
166 for (offset = 0; offset < len; offset += n) {
167 bool copy;
168
169
170
171
172 job_sleep_ns(&s->common.job, delay_ns);
173 if (job_is_cancelled(&s->common.job)) {
174 break;
175 }
176
177 ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base), false,
178 offset, COMMIT_BUFFER_SIZE, &n);
179 copy = (ret == 1);
180 trace_commit_one_iteration(s, offset, n, ret);
181 if (copy) {
182 ret = commit_populate(s->top, s->base, offset, n, buf);
183 bytes_written += n;
184 }
185 if (ret < 0) {
186 BlockErrorAction action =
187 block_job_error_action(&s->common, false, s->on_error, -ret);
188 if (action == BLOCK_ERROR_ACTION_REPORT) {
189 goto out;
190 } else {
191 n = 0;
192 continue;
193 }
194 }
195
196 job_progress_update(&s->common.job, n);
197
198 if (copy) {
199 delay_ns = block_job_ratelimit_get_delay(&s->common, n);
200 } else {
201 delay_ns = 0;
202 }
203 }
204
205 ret = 0;
206
207out:
208 qemu_vfree(buf);
209
210 return ret;
211}
212
213static const BlockJobDriver commit_job_driver = {
214 .job_driver = {
215 .instance_size = sizeof(CommitBlockJob),
216 .job_type = JOB_TYPE_COMMIT,
217 .free = block_job_free,
218 .user_resume = block_job_user_resume,
219 .run = commit_run,
220 .prepare = commit_prepare,
221 .abort = commit_abort,
222 .clean = commit_clean
223 },
224};
225
226static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs,
227 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags)
228{
229 return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
230}
231
232static void bdrv_commit_top_refresh_filename(BlockDriverState *bs)
233{
234 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
235 bs->backing->bs->filename);
236}
237
238static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c,
239 const BdrvChildRole *role,
240 BlockReopenQueue *reopen_queue,
241 uint64_t perm, uint64_t shared,
242 uint64_t *nperm, uint64_t *nshared)
243{
244 *nperm = 0;
245 *nshared = BLK_PERM_ALL;
246}
247
248
249
250static BlockDriver bdrv_commit_top = {
251 .format_name = "commit_top",
252 .bdrv_co_preadv = bdrv_commit_top_preadv,
253 .bdrv_co_block_status = bdrv_co_block_status_from_backing,
254 .bdrv_refresh_filename = bdrv_commit_top_refresh_filename,
255 .bdrv_child_perm = bdrv_commit_top_child_perm,
256};
257
258void commit_start(const char *job_id, BlockDriverState *bs,
259 BlockDriverState *base, BlockDriverState *top,
260 int creation_flags, int64_t speed,
261 BlockdevOnError on_error, const char *backing_file_str,
262 const char *filter_node_name, Error **errp)
263{
264 CommitBlockJob *s;
265 BlockDriverState *iter;
266 BlockDriverState *commit_top_bs = NULL;
267 Error *local_err = NULL;
268 int ret;
269
270 assert(top != bs);
271 if (top == base) {
272 error_setg(errp, "Invalid files for merge: top and base are the same");
273 return;
274 }
275
276 s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL,
277 speed, creation_flags, NULL, NULL, errp);
278 if (!s) {
279 return;
280 }
281
282
283 s->base_read_only = bdrv_is_read_only(base);
284 if (s->base_read_only) {
285 if (bdrv_reopen_set_read_only(base, false, errp) != 0) {
286 goto fail;
287 }
288 }
289
290
291
292 commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, filter_node_name, 0,
293 errp);
294 if (commit_top_bs == NULL) {
295 goto fail;
296 }
297 if (!filter_node_name) {
298 commit_top_bs->implicit = true;
299 }
300
301
302 commit_top_bs->never_freeze = true;
303
304 commit_top_bs->total_sectors = top->total_sectors;
305
306 bdrv_append(commit_top_bs, top, &local_err);
307 if (local_err) {
308 commit_top_bs = NULL;
309 error_propagate(errp, local_err);
310 goto fail;
311 }
312
313 s->commit_top_bs = commit_top_bs;
314
315
316
317 assert(bdrv_chain_contains(top, base));
318 for (iter = top; iter != base; iter = backing_bs(iter)) {
319
320
321
322
323 ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
324 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE,
325 errp);
326 if (ret < 0) {
327 goto fail;
328 }
329 }
330
331 if (bdrv_freeze_backing_chain(commit_top_bs, base, errp) < 0) {
332 goto fail;
333 }
334 s->chain_frozen = true;
335
336 ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp);
337 if (ret < 0) {
338 goto fail;
339 }
340
341 s->base = blk_new(s->common.job.aio_context,
342 BLK_PERM_CONSISTENT_READ
343 | BLK_PERM_WRITE
344 | BLK_PERM_RESIZE,
345 BLK_PERM_CONSISTENT_READ
346 | BLK_PERM_GRAPH_MOD
347 | BLK_PERM_WRITE_UNCHANGED);
348 ret = blk_insert_bs(s->base, base, errp);
349 if (ret < 0) {
350 goto fail;
351 }
352 blk_set_disable_request_queuing(s->base, true);
353 s->base_bs = base;
354
355
356 s->top = blk_new(s->common.job.aio_context, 0, BLK_PERM_ALL);
357 ret = blk_insert_bs(s->top, top, errp);
358 if (ret < 0) {
359 goto fail;
360 }
361 blk_set_disable_request_queuing(s->top, true);
362
363 s->backing_file_str = g_strdup(backing_file_str);
364 s->on_error = on_error;
365
366 trace_commit_start(bs, base, top, s);
367 job_start(&s->common.job);
368 return;
369
370fail:
371 if (s->chain_frozen) {
372 bdrv_unfreeze_backing_chain(commit_top_bs, base);
373 }
374 if (s->base) {
375 blk_unref(s->base);
376 }
377 if (s->top) {
378 blk_unref(s->top);
379 }
380 if (s->base_read_only) {
381 bdrv_reopen_set_read_only(base, true, NULL);
382 }
383 job_early_fail(&s->common.job);
384
385
386 if (commit_top_bs) {
387 bdrv_replace_node(commit_top_bs, top, &error_abort);
388 }
389}
390
391
392#define COMMIT_BUF_SIZE (2048 * BDRV_SECTOR_SIZE)
393
394
395int bdrv_commit(BlockDriverState *bs)
396{
397 BlockBackend *src, *backing;
398 BlockDriverState *backing_file_bs = NULL;
399 BlockDriverState *commit_top_bs = NULL;
400 BlockDriver *drv = bs->drv;
401 AioContext *ctx;
402 int64_t offset, length, backing_length;
403 int ro;
404 int64_t n;
405 int ret = 0;
406 uint8_t *buf = NULL;
407 Error *local_err = NULL;
408
409 if (!drv)
410 return -ENOMEDIUM;
411
412 if (!bs->backing) {
413 return -ENOTSUP;
414 }
415
416 if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||
417 bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) {
418 return -EBUSY;
419 }
420
421 ro = bs->backing->bs->read_only;
422
423 if (ro) {
424 if (bdrv_reopen_set_read_only(bs->backing->bs, false, NULL)) {
425 return -EACCES;
426 }
427 }
428
429 ctx = bdrv_get_aio_context(bs);
430 src = blk_new(ctx, BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
431 backing = blk_new(ctx, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
432
433 ret = blk_insert_bs(src, bs, &local_err);
434 if (ret < 0) {
435 error_report_err(local_err);
436 goto ro_cleanup;
437 }
438
439
440 backing_file_bs = backing_bs(bs);
441
442 commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, NULL, BDRV_O_RDWR,
443 &local_err);
444 if (commit_top_bs == NULL) {
445 error_report_err(local_err);
446 goto ro_cleanup;
447 }
448
449 bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort);
450 bdrv_set_backing_hd(bs, commit_top_bs, &error_abort);
451
452 ret = blk_insert_bs(backing, backing_file_bs, &local_err);
453 if (ret < 0) {
454 error_report_err(local_err);
455 goto ro_cleanup;
456 }
457
458 length = blk_getlength(src);
459 if (length < 0) {
460 ret = length;
461 goto ro_cleanup;
462 }
463
464 backing_length = blk_getlength(backing);
465 if (backing_length < 0) {
466 ret = backing_length;
467 goto ro_cleanup;
468 }
469
470
471
472
473 if (length > backing_length) {
474 ret = blk_truncate(backing, length, false, PREALLOC_MODE_OFF,
475 &local_err);
476 if (ret < 0) {
477 error_report_err(local_err);
478 goto ro_cleanup;
479 }
480 }
481
482
483
484 buf = blk_try_blockalign(src, COMMIT_BUF_SIZE);
485 if (buf == NULL) {
486 ret = -ENOMEM;
487 goto ro_cleanup;
488 }
489
490 for (offset = 0; offset < length; offset += n) {
491 ret = bdrv_is_allocated(bs, offset, COMMIT_BUF_SIZE, &n);
492 if (ret < 0) {
493 goto ro_cleanup;
494 }
495 if (ret) {
496 ret = blk_pread(src, offset, buf, n);
497 if (ret < 0) {
498 goto ro_cleanup;
499 }
500
501 ret = blk_pwrite(backing, offset, buf, n, 0);
502 if (ret < 0) {
503 goto ro_cleanup;
504 }
505 }
506 }
507
508 if (drv->bdrv_make_empty) {
509 ret = drv->bdrv_make_empty(bs);
510 if (ret < 0) {
511 goto ro_cleanup;
512 }
513 blk_flush(src);
514 }
515
516
517
518
519
520 blk_flush(backing);
521
522 ret = 0;
523ro_cleanup:
524 qemu_vfree(buf);
525
526 blk_unref(backing);
527 if (backing_file_bs) {
528 bdrv_set_backing_hd(bs, backing_file_bs, &error_abort);
529 }
530 bdrv_unref(commit_top_bs);
531 blk_unref(src);
532
533 if (ro) {
534
535 bdrv_reopen_set_read_only(bs->backing->bs, true, NULL);
536 }
537
538 return ret;
539}
540